1. Field of Invention
The present invention relates to an optical component using glass, and a projector for projecting and displaying an image using the optical component.
2. Description of Related Art
In a projector, an image is displayed by modulating light which has exited from an illumination optical system using, for example, a liquid crystal light valve in accordance with image information (that is, an image signal), and by projecting the modulated light onto a screen.
The above-described projector includes various optical components using glass. For example, in the liquid crystal light valve, an optical component comprising a polarizer provided on a glass substrate is used. This optical component includes the polarizer and the glass substrate, with adhesive being used to affix the polarizer onto the glass substrate. In general, the surface of the substrate is finished to a mirror-smooth state in order to prevent scattering of light at the surface of the substrate.
However, it is troublesome to produce an optical component such as that described above. This is because, when the surface of the glass substrate is finished to a mirror-smooth state, it is usually necessary to perform grinding, lapping, and polishing for a long period of time. This problem also exists in various other types of optical components using glass.
In order to overcome the above-described conventional problem, it is an object of the present invention to provide a technology which makes it possible to easily produce an optical component without considerably deteriorating the optical characteristics of the optical component.
In order to solve at least a part of the above-described problem, in accordance with an exemplary embodiment of the present invention, there is provided an optical component which may consist of:
a glass substrate;
an optical member connected to the glass substrate; and
a connecting layer for connecting a connecting surface of the glass substrate and a connecting surface of the optical member together.
According to this exemplary embodiment, the connecting surface of the glass substrate is defined as the surface which passes therethrough light which is processed by the optical component, and has a roughness of approximately 3 nm to approximately 10 nm in terms of the root mean square value.
In the optical component according to another exemplary embodiment, the connecting surface of the glass substrate is formed as a rough surface like that described above. However, the glass substrate and the optical member are connected together by covering the projections and depressions of the rough surface with the connecting layer. Accordingly, since the scattering of light at the rough surface can be reduced by the connecting layer, it is possible to easily produce the optical component without considerably deteriorating the optical characteristics of the optical component.
In the optical component according to another exemplary embodiment, it is preferable that the index of refraction of the connecting layer be approximately 1.2 to approximately 1.5.
When the index of refraction of the joining layer is in the above range, it is substantially the same as the index of refraction of the glass substrate, making it possible to reduce deterioration in the optical characteristics of the optical component.
In the optical component according to another exemplary embodiment, it is preferable that the ratio of the index of refraction of the joining layer to the index of refraction of the glass be from approximately 0.8 to approximately 1.2.
When the ratio of the index of refraction of the connecting layer to that of the glass substrate is in the above range, it is possible to considerably reduce deterioration in the optical characteristics of the optical component.
In the optical component according to another exemplary embodiment, the optical member may be a polarizer, or a retardation film, or a lens.
In the optical component according to another exemplary embodiment, the optical member may be a light-transmissive member which has a polarization separation film formed on the connecting surface thereof.
In the optical component according to another exemplary embodiment, the optical member may be a light-transmissive member which has a selection film for selecting light of a predetermined wavelength range formed on the joining surface thereof.
Accordingly, various optical components may be connected to the glass substrate.
In the optical component according to another exemplary embodiment, the glass substrate may be sapphire glass.
Since sapphire glass has a relatively high hardness, it is relatively difficult to finish the surface thereof to a mirror-smooth state. Therefore, an optical component which uses sapphire glass can be very easily produced.
In the optical component according to another exemplary embodiment, an antireflection film may be formed on a surface of the optical component which contacts the air and passes therethrough light which is processed by the optical component.
This makes it possible to prevent reflection at the surface which contacts the air and passes light therethrough, so that the optical characteristics of the optical component is improved.
In accordance with another exemplary embodiment of the present invention, there is provided an optical component which may consist of:
a plurality of first and second glass substrates alternately disposed along a predetermined direction;
connecting layers for connecting connecting surfaces of the first glass substrates and corresponding connecting surfaces of the second glass substrates; and
polarization separation films and reflective films alternately disposed at interfaces between the first glass substrates and the corresponding second glass substrates;
In this exemplary embodiment, at the interfaces where the polarization separation films are formed, the connecting surfaces of the first glass substrates each have a roughness of approximately 3 nm to approximately 10 nm in root mean square value, the polarization separation films are formed on the corresponding second glass substrates, and the connecting layers are formed between the corresponding polarization separation films and the corresponding first glass substrates.
In the optical component according to this exemplary embodiment, the connecting surfaces of the corresponding first glass substrates are formed as rough surfaces. However, the first and second glass substrates are connected together by covering the projections and depressions of the rough surfaces with the corresponding connecting layers. Therefore, it is possible to easily produce the optical component without considerably deteriorating the optical characteristics of the optical component.
In accordance with another exemplary embodiment of the present invention, there is provided an optical component which may consist of:
four columnar glass prisms divided at interfaces forming into a substantially X shape; and
connecting layers for connecting connecting surfaces of the four corresponding columnar glass prisms.
In this exemplary embodiment, at least two adjacent columnar glass prisms selected from the four columnar glass prisms are such that the joining surface of the first columnar glass prism has a roughness of approximately 3 nm to approximately 10 nm in root mean square value, the second columnar glass prism has a selection film for selecting light of a predetermined wavelength range formed thereon, and the connecting layer of the first columnar glass prism is formed between the selection film and the first columnar prism.
In the optical component according to another exemplary embodiment, the connecting surface of the selected first columnar glass prism is formed as a rough surface. However, the two columnar glass prisms are connected together by covering the projections and depressions of the rough surface with the joining layer. Therefore, the optical component can be easily produced without considerably deteriorating the optical characteristics of the optical component.
Various types of projectors may include the optical components of the present invention. For example, according to another exemplary embodiment of the present invention there may be provided a projector which may consist of:
an illumination optical system which causes an illumination light beam to exit therefrom;
an electro-optical device for modulating the light beam from the illumination optical system in accordance with image information; and
a projection optical system for projecting the modulated light beam obtained by the electro-optical device.
The optical component of this exemplary embodiment is provided in any one of the illumination optical system, the electro-optical device, and the projection optical system.
According to another exemplary embodiment of the present invention, there may also be provided a projector which may consist of:
an illumination optical system which causes an illumination light beam to exit therefrom;
an electro-optical device for modulating the light beam from the illumination optical system in accordance with image information; and
a projection optical system for projecting the modulated light beam obtained by the electrooptical device.
The illumination optical system of this exemplary embodiment may consist of:
a polarization generation section which causes a predetermined polarized light beam to exit therefrom, the polarization generation section may consist of an optical component for separating the light beam incident thereupon into two types of polarized light beams, and a selection retardation film for making one of the two types of polarized light beams which exit from the optical component the same as the other of the two types of polarized light beams.
According to another exemplary embodiment of this invention, there is provided a projector for projecting and displaying a color image, which may consist of:
an illumination optical system which causes an illumination light beam to exit therefrom;
a color light separation optical system for separating the illumination light beam which has exited from the illumination optical system into light beams of three color components, a first color light beam, a second color light beam, and a third color light beam;
a first electro-optical device, a second electro-optical device and a third electro-optical device for generating a first modulated light beam, second modulated light beam, and a third modulated light beam, respectively, as a result of modulating in accordance with image information the first color light beam, the second color light beam and the third color light beam separated by the color light separation optical system;
a color light synthesizing optical system for synthesizing the first modulated light beam, the second modulated light beam and the third modulated light beam; and
a projection optical system for projecting the synthesized light beams which exit from the color light synthesizing optical system.
In this exemplary embodiment, an optical component is provided in any one of the illumination optical system, the color light separation optical system, the first electro-optical device, the second electro-optical device, the third electro-optical device, the color light synthesizing optical system, and the projection optical system.
According to another exemplary embodiment of this invention, there is provided a projector for projecting and displaying a color image, which may consist of:
an illumination optical system which causes an illumination light beam to exit therefrom;
a color light separation optical system for separating the illumination light beam which has exited from the illumination optical system into light beams having three color components, a first color light beam, a second light beam and a third color light beam;
a first electro-optical device, a second electro-optical device and a third electro-optical device for generating a first modulated light beam, a second modulated light beam and a third modulated light beam, respectively, as a result of modulating in accordance with image information the first color light beam, the second color light beam and the third color light beam separated by the color light separation optical system;
a color light synthesizing optical system for synthesizing the first modulated light beam, the second modulated light beam and the third modulated light beam; and
a projection optical system for projecting the synthesized light beams which exit from the color light synthesizing optical system.
In this exemplary embodiment, the third optical component is provided in either one of the color light separation optical system and the color light synthesizing optical system.
Since these projectors include the above-described optical components, it is possible to easily produce these projectors without considerably deteriorating the optical characteristics of the projectors.